The Cleaning Crew

Hi all

i am setting up my reef tank and i am using red sea reef mature pro kit..

this makes tanks ready in 21 days ...

anyway i am on day 10 which is time to add the cleaning crew in.

i went to my local stockist and he sold me 3 snails and 2 hermit crabs ...

do i need more or is this enough for the cleaning process

my tank is 230ltrs/50 gallon

it recommends on the instructions ...

brittle starfish,detritus feeding cucumbers and several herbivorous snailssuch as asraea tucta or turban snail...

it doesnt state how many of each tho ???

any ideas ?? if i need more i will get them tomo

thanks